A follow-up study of respiratory and physical function after discharge in patients with redetectable positive SARS-CoV-2 nucleic acid results following recovery from COVID-19

OBJECTIVE: The aim of this study was to evaluate the respiratory and physical function of patients who retested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA during post-coronavirus disease 2019 (COVID-19) rehabilitation. METHODS: A total of 302 discharged COVID-19 patients were included. Discharged patients were followed up for 14 days to 6 months. The modified Medical Research Council (mMRC) dyspnea scale, Borg rating of perceived exertion, and manual muscle testing (MMT) scores on day 14 and at 6 months after discharge were compared between the redetectable positive (RP) and non-RP (NRP) groups. Prognoses of respiratory and physical function were compared between patients who recovered from moderate and severe COVID-19. RESULTS: Of the study patients, 7.6% were RP. The proportion of patients who used antiviral drugs was significantly lower in the RP group than in the NRP group. There were no differences in mMRC, Borg, or MMT scores within the RP and NRP groups. The mMRC, Borg, and MMT scores were worse for patients with severe disease when compared to those with moderate disease at both follow-up time points. CONCLUSIONS: COVID-19 patients who did not take antiviral drugs were more likely to be RP after discharge. The recovery of respiratory and physical function was not related to re-positivity during rehabilitation, but was related to disease severity during hospitalization.